Abstract 3000: New epigenetic biomarker for colorectal cancer.

Abstract

Abstract DNA is released and circulate in the blood of cancer patients. Epigenetic changes in the levels of circulating DNA has been associated with tumor burden and malignant progression. Public physical examination recommends occult fecal blood test for colorectal cancer (CRC) screening but its false positive rate is too high. As for serum marker for CRC including CEA and CA19-9, their sensitivity are nor satisfactory especially in early stage CRC patients and therefore, the potential use of circulating DNA for CRC screening has emerged. The aim of this study is the clinical utility of cell-free DNA as blood biomarkers. Based on our previous report about the new methylation markers for CRC on a genome-wide scale, we selected 4 methylation markers positive for CRC and established CRC screening panel. First, we collected plasma DNA from blood samples of 100 CRC patients preoperatively and 50 age-matched healthy volunteers. Then, we performed pyrosequence about plasma DNA after bisulfite treatment. Using this cancer screening panel, 82 CRC patients were positive for at least 1 marker. On the other hand, no control samples were positive for any markers and therefore, sensitivity and specificity using this cancer screening panel for CRC were 82.0% and 100%, respectively. According to TNM classification, positive rate for earlier stage including 1 and 2 patients were lower than advanced CRC patients. Similarly, the patients with abnormal serum CEA level harbored higher positive rate for the cancer panel, but serum CA19-9 level which is another CRC marker was not associated with positive rate. Two markers of the panel were relatively high in old age although they were negative for control samples. Considering that no hypermethylation was detected in control samples, this cancer panel is superior to preexisting blood tumor markers for CRC and available for cancer screening. Citation Format: Kiyoko Takane, Yutaka Midorikawa, Koichi Yagi, Ayako Sakai, Hiroyuki Aburatani, Tadatoshi Takayama, Atsuhi Kaneda. New epigenetic biomarker for colorectal cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3000. doi:10.1158/1538-7445.AM2013-3000